This invention relates to a cab structure for a heavy motor vehicle of the type in which the cab is disposed in a forward position in the frame.
Structures of this type comprise substantially a floor, two sides, a front and a rear wall, and are constructed by normally using welding to rigidly join together structural elements each of which is formed by joining together a plurality of sheet metal elements of fairly complex shape. The structural elements formed in this manner are provided with connection parts which are shaped to generate cross-members, longitudinal members or struts, and are mounted so that they superpose corresponding parts of the adjacent structural elements either to allow them to be joined together or to give high rigidity and mechanical strength to the structure. Cab structures formed by joining together such structural elements have numerous drawbacks.
Firstly, to construct cabs of one and the same series but for use on vehicles of different dimensions, a large number of structural elements are required because each can be used on only one cab of particular dimensions, and therefore each cab of the series can be constructed only by using one particular combination of structural elements.
In addition, in certain cases the mechanical strength and rigidity of the obtained structure are not very high, particularly because of the large number of connection zones between the various sheet metal elements which comprise the structural elements.
Again, the cabs obtained are very complicated because of the shape of the relative structural elements, and lengthy operations are involed in their construction. In this respect, each structural element is provided with the aforesaid connection elements and these must be kept in their correct relative position when joining the various elements. In particular, with such structural elements it is very difficult and in some cases impossible to automate cab assembly using welding robots.
Finally, the storage and transportation of such structural elements is not simple because of their size.